[PATCH v3 1/3] security: Introduce LSM_ORDER_LAST and set it for the integrity LSM

[Paul Moore]

On Thu, Mar 9, 2023 at 3:55 AM Roberto Sassu
<roberto.sassu at huaweicloud.com> wrote:
>
> From: Roberto Sassu <roberto.sassu at huawei.com>
>
> Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs needing to be
> last, e.g. the 'integrity' LSM, without changing the kernel command line or
> configuration.
>
> Also, set this order for the 'integrity' LSM. While not enforced, this is
> the only LSM expected to use it.
>
> Similarly to LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled
> and put at the end of the LSM list.

Since you are respinning this patchset anyway, I might make it clear
that the LSM_ORDER_LAST LSMs are always enabled only when they are
enabled at kernel configure/build time.  Simply marking a LSM as
LSM_ORDER_LAST does not mean you don't have to explicitly select the
LSM in the rest of the Kconfig.

> Finally, for LSM_ORDER_MUTABLE LSMs, set the found variable to true if an
> LSM is found, regardless of its order. In this way, the kernel would not
> wrongly report that the LSM is not built-in in the kernel if its order is
> LSM_ORDER_LAST.
>
> Fixes: 79f7865d844c ("LSM: Introduce "lsm=" for boottime LSM selection")
> Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
> ---
>  include/linux/lsm_hooks.h |  1 +
>  security/integrity/iint.c |  1 +
>  security/security.c       | 12 +++++++++---
>  3 files changed, 11 insertions(+), 3 deletions(-)

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